Accumulating data indicate reactive oxygen intermediates (ROI = superoxide and hydrogen peroxide) function in signaling cell growth and that aberrant signaling by this mechanism contributes to the aggressive growth characteristics of cancers, including melanoma. The laboratories of Drs. Lambeth and Jones will collaborate to investigate the role of a novel RO1-producing oxidase in control of melanoma cell proliferation. Dr. Lambeth's laboratory is expert in the enzymatic generation of RO1, while Dr. Jones' laboratory is uniquely qualified to assess redox signalling within cells. While neither laboratory has previously worked on melanoma, the two provide unique expertise and intellectual resources which can be directed to melanoma research. This proposal is designed to provide preliminary data which will be used to support an RO1 application.